Rope Stopper System

ABSTRACT

A rope stopper system for a fibre rope ( 30 ) is described, where a rope stopper ( 10 ) is placed on a deck of an anchor handling vessel ( 50 ) or the like, and is arranged to grip and secure the fibre rope ( 30 ), that runs through the rope stopper ( 10 ), in connection with reshackling and the like. The rope stopper ( 10 ) comprises a frame ( 12 ) equipped with at least three rotary stopper elements ( 14 ), where the stopper elements ( 14 ) are arranged in an opening ( 16 ) in the frame ( 12 ), said opening ( 16 ) is a through-running opening to receive the fibre rope ( 30 ), and where the stopper elements ( 14 ) in the opening are placed about the through-running fibre rope ( 30 ), and also that the surface of said stopper elements ( 14 ) is equipped with a contact surface ( 24 ) which, during rotation of the stopper elements, is arranged to lock the fibre rope ( 30 ) and that the contact surface is arranged at a point on the outer surface ( 26 ) that lies further away from the bearing point ( 20 ) of the stopper element than at least the most of the other points in the outer surface ( 26 ) of the stopper element.

The present invention relates to a rope stopper system for a fibre rope,where a rope stopper is placed on a deck of an anchor handling vessel orthe like, and is arranged to grip and secure the fibre rope that runsthrough the rope stopper, in connection with reshackling and the like.

On, for example, an anchor handling vessel, a towing pin is often usedto steer and guide a chain, wire, cable, or the like to the mouth areaof a shark jaw. A shark jaw is normally used to grip and secure saidchain or cable. Such shark jaws are normally formed to hold and griparound the chain or cable, for example, in connection with reshacklingor other operations.

Fibre ropes have gradually been used for the handling of heavy loads inthe form of, for example, anchors and subsea equipment for the oil andgas industry. Fibre ropes are now used more and more at great oceandepths, as such ropes have a lower specific weight and thereby make theheavy lifting easier. A shark jaw as described above is not suited to beused on fibre ropes. Therefore, it is possible to use the presentinvention instead of a shark jaw, or alternatively in addition to suchequipment.

From prior art, reference is made to WO 2007/021195A1, which describes acentring device that is arranged to guide and grip a wire, chain, cable,etc. The device comprises a box mounted on a deck of a vessel, and whichis fitted with at least two rotary guiding plates, where the guidingplates with contact surfaces can have an eccentric or oval shape and canrotate about a bearing point. The guiding plates are arranged so thatthey shall guide or grip the rope between the respective guiding plates.Contrary to the present invention, the guiding plates are, in the main,arranged transversely to said wire, chain or cable, so that when theguiding plates are raised, the end edges of the guiding plates arearranged to lie against said wire, chain or cable to counteract theassociated rotation.

Furthermore, reference is made to US 2004/187757 A1 which shows anexample of a rope stopper that is commonly used on yachts. The ropestopper comprises a base with two stopper elements that can rotate abouta bearing point. The stopper elements have a cylindrical or oval shapewith a contact surface for the gripping of the rope.

Consequently, it is an object of the present invention to provide asolution that can be used to grip and secure fibre ropes on a vessel,such as an anchor handling vessel that is used in connection withoffshore operations, and which simple and easy to use.

A further object is also to provide a solution that can easily be movedaround the deck of the vessel and can simply be placed next to existingequipment on the deck.

The above mentioned objects are reached with a rope stopper system for afibre rope, where a rope stopper is placed on the deck of an anchorhandling vessel or the like and is arranged to grip and secure the fibrerope that runs through the rope stopper, in connection with reshacklingand the like. The rope stopper comprises a frame equipped with at leastthree rotary stopper elements, where the stopper elements are arrangedin an opening in the frame, said opening is an opening for the fibrerope to run through, and where the stopper elements in the opening areplaced about the fibre rope running through, and also that the outersurface of said stopper element is equipped with a contact surfacewhich, during rotation of the stopper element, is arranged to lock thefibre rope, and that the contact surface is arranged at a point on theouter surface that lies further away from the bearing point of thestopper element than at least most of the other points of the outersurface of the stopper element.

Alternative embodiments are given in the respective dependent claims.

Said stopper element can be supported eccentrically with respect to thecontact surface of the stopper element with the fibre rope.

The stopper element can have an eccentric shape or an oval shape.Furthermore, the contact surface can have an external curved radius,and/or the contact surface can be equipped with a rubber covering. Thecurved shape of the contact surface, or the rubber covering, can changewith the circumference about the stopper element.

The frame can be equipped with a number of back supports, whereby therope stopper is arranged to be placed next to other equipment on thedeck of the vessel.

Said back supports can be arranged to be placed between the cylinders ofa towing pin.

Furthermore, the stopper elements can be arranged to be rotated insynchrony.

The frame can comprise a motor connected to one of the stopper elements,and said stopper element is preferably connected via a drive unit to theother stopper elements.

The invention shall now be described in more detail with the help of theenclosed figures, in which:

FIG. 1 shows a principle drawing of an example of an anchor handlingvessel that can use the present invention.

FIG. 2 shows in more detail the aft end of the vessel shown in FIG. 1.

FIGS. 3 and 4 show a rope stopper according to the invention in an openand closed position, respectively, and placed next to a towing pin.

FIGS. 5 and 6 show schematics of the rope stopper according to theinvention.

FIGS. 7, 8 and 9 show a front schematic of the rope stopper according tothe invention and with stopper elements in different positions.

FIGS. 10, 11 and 12 show different schematics of a stopper elementaccording to the invention.

FIG. 13 show an alternative embodiment of a rope stopper according tothe invention.

FIG. 1 shows a principle drawing of an anchor handling vessel 50 thatcan be equipped with the solution according to the invention. FIG. 2shows in more detail an aft end 52 of the vessel 50, and shows a rope inthe form of a fibre rope 30 that runs on a deck 54, from a winch (notshown) placed further forward on the deck, and over, for example, aroller at the aft end and down into the sea. The fibre rope 30 can, inthis connection, be used for handling of heavy loads in the form of, forexample, anchors and subsea equipment for the oil and gas industry. Atgreat ocean depths fibre ropes are being used more and more, as suchropes have a lower specific weight and thus make heavy lifts easier.

A rope stopper 10 according to the invention can be placed at the aftend 52, or anywhere on the deck 54 for that matter. However, in theembodiment example shown the rope stopper 10 is shown placed adjoining atowing pin 40 which is normally used to steer and guide a chain, wire,cable or the like to the mouth area of a shark jaw (nor shown). A sharkjaw 42 is indicated driven down into the deck, and is normally used forgripping and securing of said chain or cable. Such shark jaws arenormally shaped to grip the chain or the cable, and are therefore notsuited to be used with fibre ropes. Therefore, it will be possible touse the present invention instead of a such shark jaw, or alternativelyin addition to such equipment.

As FIGS. 3 and 4 show in more detail, the rope stopper 10 according tothe invention is, for example, placed next to the towing pin 40, i.e. inmore detail the rope stopper 10 rests against the two driven upcylinders 40 a, 40 b of the towing pin. To secure the rope stopper 10when it is placed in this way, the rope stopper can be equipped with twoback supports 22 (best shown in FIG. 5) that can lie internally betweenthe cylinders 40 a, 40 b of the towing pin 40. Thus, the towing pin 10can be loose or fastened between the cylinders so that it can becomeloose and the towing pin arrangement will thereby be able to take up theforces from the load, i.e. when the rope stopper 10 engages with thefibre rope 30. The back supports 22 can also comprise appliances for asecure fastening of different equipment, such as said towing pin or thelike. Alternatively, the rope stopper 10 can be placed in a box on thedeck (not shown) and in a way corresponding to the towing pin or sharkjaw be arranged to be driven up from and down into the deck 54.

In the embodiment shown, the rope stopper 10 comprises a frame 12 which,among other things, the back supports 22 are fastened to. Furthermore,the frame 12 is equipped with a downwardly directed opening 16 whereseveral stopper elements 14, also called friction wheels, are mounted sothat they can rotate. Thereby, the rope stopper 10 can be threaded overthe fibre rope 30 and rest against the cylinders 40 a, 40 b of thetowing pin 40. In the case of the rope stopper being driven up or downas described, the opening will naturally be directed upwards.

The rope stopper 10 is shown in an open position in FIG. 3, i.e. thestopper elements 14 are rotated so that they do not engage with thefibre rope 30, while FIG. 4 shows the wheels rotated so that they engagewith the fibre rope 30. The corresponding is shown in the FIGS. 7-9,where FIG. 7 shows the stopper elements 14 in an open position, FIG. 8shows the stopper elements in partially closed position or closedposition in the case of fibre ropes of a large diameter, and FIG. 9shows the stopper elements in a closed position in the case of fibreropes with smaller diameters. As the figures show, the stopper elements14 (which are, as mentioned, also called friction wheels) are mountedmutually spaced apart in the frame 12 about a central, imaginarylongitudinally running axis through the opening 16. The opening 16 is anopening through which the fibre rope 30 will run and where the stopperelements 14 in the opening are placed radially about the fibre rope 30that runs through. This axis will be able to correspond to thelongitudinal axis of the fibre rope when the fibre rope runs through theopening. Thus, the rope stopper 10 can hold different fibre ropes ofdifferent diameters. Furthermore, preferably three or more stopperelements are used so that the fibre rope can be optimally held tight.The use of, for example, three stopper elements will, of course, centrethe fibre rope.

The frame shown in the FIGS. 3-9 can also be closed at the bottom of theopening 16 with the help of stays, bolts or the like so that the frameis given an increased strength against torsion and the like.

So that the stopper elements 14 shall grip about the fibre rope 30 whenthey are rotated, they are preferably formed so that a contact surface24 meets the fibre rope 30, and where the contact surface 24 moveseccentrically with regard to a bearing point 20 for the stopper element14. Thus, the stopper elements 14 are rotated in the longitudinaldirection of the fibre rope. This is shown in FIG. 10 in that thestopper element has an eccentric form, as opposed to the circular formshown by the partial circle arch S, i.e. for example an approximate ovalform and with the bearing point 20 placed eccentrically with regard tothe centre of the form. This will be the best solution that provides themost power, but the stopper element 14 can alternatively also have anapproximately circular shape and with the bearing point eccentrically inrelation to the centre, or also in an oval or the like with the bearingpoint centrally. Most importantly is that the contact surface 24 of thestopper element 14 is arranged at a point that lies further away fromthe bearing point 20 of the stopper element than at least most of theouter surface 26 of the stopper element.

During reshackling or the like, or when tension arises in the fibre rope30, the stopper elements 14 will thereby be able to be rotated in acontrolled way, for example, counter-clockwise, (as shown in thefigures), so that the contact surfaces 24 of every element will beforced against the fibre rope for the rope to ne gripped, and duringpulling in or after reshackling of the fibre rope 30, the stopperelements 14 will, for example, be able to be rotated in a controlled wayclockwise so that the contact surfaces 24 disengage with the fibre rope,and also so that the rest of the outer surface, indicated by 26, doesnot come into contact with the fibre rope 30 either. The rope stopper 10can be equipped with means for controlled rotation of the stopperelements 14. Furthermore, the rope stopper 10 can be equipped with meansto lock the stopper elements 14 in any desired position.

FIG. 13 shows a further variant of the rope stopper 10 and comprises, ina corresponding way, a frame 12 with several stopper elements 14 placedabout an opening 16 a where the fibre rope 30 runs. Here, the ropestopper 10 is in closed form so that the opening 16 a is only athrough-running opening, contrary to the earlier variants that show anupwardly or downwardly open and through-running opening 16. In thisversion, the frame can be connected by an upper hinge 28 a, and can beopened in two frame part halves that can be opened and be threaded overthe fibre rope 30. The two frame half parts can be locked in a lowerconnection 28 b, for example, with the help of a through-running bolt orthe like. FIG. 13 shows further that the contact surfaces can be formedas a sole 24 a fitted externally onto the stopper elements 14. The sole24 a can be serrated externally, and correspondingly the contactsurfaces 24 as described previously can alternatively be serrated also.

However, it is preferred that the contact surfaces described for boththe variants are formed in an arch and have a smooth outer surface,and/or alternatively they can be equipped with a layer in the form of,for example, a rubber covering. The arched shape of the contact surfaceor the covering can change with circumference to adjust to the fibrerope for both large and small diameters, i.e. that the radius of thearched shape changes along the circumference of the stopper element.

For both variants, the stopper elements can also be controlled by amotor so that a controlled rotation and locking is provided. The stopperelements can be equipped with, or connected to, cogwheels or other driveappliances/drive units, for example, placed inside the frame 12, forsynchronous rotation of the elements. For this purpose, a hydraulicmotor, for example, can be used, indicated by the reference number 32 inFIG. 13, which is connected to the shaft of one of the stopper elements.Thereby, in activating the motor the other stopper elements will also beactivated and rotated via the cogwheels or the drive appliance. Lineartransmission can also be used.

The bearing 20 can be in the form of a shaft that is connected to saidcogwheels or drive unit.

1. Rope stopper system for a fibre rope (30), where a rope stopper (10) is placed on a deck of an anchor handling vessel (50), and is arranged to grip and secure the fibre rope (30), that runs through the rope stopper (10), in connection with reshackling, wherein the rope stopper (10) comprises a frame (12) equipped with at least three rotary stopper elements (14), where the stopper elements (14) are arranged in an opening (16) in the frame (12), said opening (16) being a through-running opening to receive the fibre rope (30), and where the stopper elements (14) in the opening are placed about the through-running fibre rope (30), and also that an outer surface of said stopper elements (14) is equipped with a contact surface (24) which, during rotation of the stopper elements, is arranged to lock the fibre rope (30), and that the contact surface is arranged at a point on the outer surface (26) that lies further away from the bearing point (20) of the stopper element than at least the most of the other points in the outer surface (26) of the stopper element.
 2. System according to claim 1, wherein said stopper element (14) is supported (20) eccentrically with regard to the contact surface (24) of the stopper element (14) with the fibre rope (16).
 3. System according to claim 1, wherein the stopper element (14) has an eccentric shape or an oval shape.
 4. System according to claim 1, wherein the contact surface (24) is shaped externally with an arched radius.
 5. System according to claim 1, wherein the contact surface (24) is equipped with a rubber covering.
 6. System according to claim 4, wherein the arched shape of the contact surface (24), or the rubber covering, changes around the circumference about the stopper element (14).
 7. System according to claim 1, wherein the frame (12) is equipped with a number of back supports (22), whereby the rope stopper (10) is arranged to be placed next to other equipment on the deck (54) of the vessel.
 8. System according to claim 7, wherein said back supports (22) are arranged to be placed between the cylinders (40 a, 40 b) of a towing pin (40).
 9. System according to claim 1, wherein the stopper elements (14) are arranged for synchronous rotation.
 10. System according to claim 1, wherein the frame comprises a motor (32) connected to one of the stopper elements (14) and that said stopper element is connected via a drive unit with the other stopper elements.
 11. System according to claim 5, wherein the arched shape of the contact surface (24), or the rubber covering, changes around the circumference about the stopper element (14). 